Fastening



Patented Feb. 23, 1937 UNITED STATE FASTENING Frank H. Ellsworth andGeorge" A. Gleason, Worcester, Mass, assignors to The-.American Steeland Wire Company of New Jersey, a corporation of New Jersey No, Drawing.

. ,3 Claims.

This invention relates to metal fasteners of the type intendedforfrictional insertion in wood. Such fastenings may be in the form ofnails, screws, etc., all of which depend upon' frictional 5 engagementwith wood for their holding power.

In an effort to increase the security of such fastenings, cementcoatings of various sorts are sometimes applied to their surfaces.Although these coatingsprovide an increased frictional copose forthereason that the coatings themselves donot firmly adhere to thefasteningsfi A fastening embodying the features ofthe present inventionis characterized by having a coating consisting of any of the resins of"glycerolphthalic acid, this coating adhering firmly and tenaciously tothe fastening and having a high coreacting glycerol with a phthalic andan aliphatic acid, this coating also being characterized. in thedescribed manner' and, in addition, havi a perior toughnes a One methodof making a resin, of the character described is by slowly heatingglycerdlfland iphthalic fanhydride together.- Experimentation will-showthat when this is-conductedin the Application January 21, Serial No.2,838

. eflicient they generally fail in their intended pur-' mentionedresins, this coating being consequently desired will result.

s PATENT OFFICE This resin ,may be dissolved in a suitable solvent forthe purpose of effecting its application to the fastenin'gs. The heatingtogether of phthalic acid and any of the aliphatic acids with the glycerol results in a resin having a toughness not possessed by the singleacid product. The resulting resin may be applied to the fasteningsthrough" the medium of a suitable solvent,

and will produce coating.

a product having a tougher The solvent mentioned-above should be ofahighly, volatile nature. A solution of the "resin and solvent is appliedto the fastenings without baking, ordinary nail tumblers being apractical apparatus for effecting the application. No dry- [ing orsemi-drying -We claim 5 oils can be used.

a '1. A metal fastening constructed for'frictional insertion in wood andcharacterized by coating consisting "of any of the resins of having a,f' phthalic 'acid,1said coating adhering firmly and tenaciously tosaidfastening andhaving a high coeflicient of friction with wood.

2. A wire nail having a coating consisting of I any. of the resins ofglycerol-phthalic acid, said coating adhering firmly and tenaciouslytosaid fastening and'having a high coefficie? of friction with'wood. 3. Awire nail h ,resinmade by reacting gl and an aliphatic aving acoatingconsisting of a ycerol with a phthalic acid, said coating adheringfirndy'and tenaciously to said fastening and having a high coe propermanner a resilient resinof the character mcient of friction with wood.

FRANK H. Euswoa'rn. GEORGE A. GLEASON.

glycerol- 20

